yeah i was looking at Jonathans post/ thread on this issue- looks like an interesting idea-!

is the problem that it can 'twist' in it's on length- or just it flapping about in the breeze getting its wobble on?!

my slight problem in this build will be the machining of the parts etc, as i'm yet to get a mill and lathe- but want.... hence my initial though of R&P.

i guess it's a toss up between the 2 as the ball screw method may be costly compared to a realtively cheap r & p...

keep going round and round and round with these decisions- sorry to keep asking pretty much the same questions over and over-!!

G